Another 70-71 Clutch Issue

rw7810 · rw7810's Garage

I sent this by PM to Grady due to his expertise, but wanted the whole board to benefit. At any rate, having problem going back together with my clutch. I'm putting my 70 tranny back on after replacing a broken ball pin. I've done this probably about 4 times over the last 15-16 years without much trouble. This time, things just seem too loose. When I pull the fork towards the front of the tranny so I can move the throwout bearing ears under the fork fingers, it is not as snug as I remember in the past. Once the fingers are behind the ears, the fork is still loose, can wiggle freely. When pushed up snug with the throwout bearing ears it is not riding on the tensioner spring underneath it. It seems as if the pressure plate fingers/tynes have weakened over time and released away from disk causing this change in geometry. Is that possible?? Any suggestions?? Yes, have the conical washer and spring mounted under the fork. I bought the fork new about 5 years ago.

I've read this post and inspected the pressure plate but didn't see anything wrong. '70 clutch still broken, help needed to make race

Grady Clay · 03-05-2006, 12:47 PM

Bob,

I got you e-mail (I intentionally leave my in-box on forums, etc. full so I only have to deal with my MSN in-box and my USPS mail box. KISS principal)

What exactly did you do with the clutch?
What got removed and reinstalled?
What got replaced?
What were the symptoms that initiated this?

Do you think the pressure plate diaphragm spring fingers have changed position?

Is it possible that the finger spring was prior located between the ball pivot and the conical washer and is now (correctly) positioned between the conical washer and the case?

I would disassemble the pressure plate off the flywheel and inspect everything. When installing and removing the pressure plate be very slow and methodical to keep the pressure plate square to the flywheel and move it only a little at a time. I think many of the pressure plate casting and diaphragm spring failures are from too hasty removal and installation.

Best,
Grady

rw7810 · rw7810's Garage

Yes, the spring was and is back under the conical washer. Could it be that I just need to give it some more bend so that it keeps a constant pressure on the fork thus giving it constant pressure on the throwout bearing ears??

I had everything apart to replace a broken ball pin. I remove the pressure plate as you have suggested in the past to clean an inspect. I didn't see any problem with it.

Grady Clay · 03-05-2006, 01:34 PM

Bob,

Based on your observation that something changed I would look carefully. Yes, you can simply bend the finger spring for proper contact.

I would also compare the broken pivot (if you have both pieces) to the replacement. If you can find the rotational orientation, some Super Glue would work for measuring purposes (just remember to throw it away or break it afterwards). It’s conceivable there could be a difference in dimensions. I have an original one I can measure for you.

In your collection of old stuff do you have the early version pivot with the nut and plastic hemisphere?

Best,
Grady

rw7810 · rw7810's Garage

Grady - well, after posting my email, I went back out, removed the tranny and put a little more bend in the spring. It went back together well and the fit is much better: no looseness in the fork as before. At any rate, less expensive than a new pressure plate at least for now. Yes, the dimensions of the ball pin were the same.

I don't have the early version pivot with the nut and plastic hemisphere you refer to, I thought that was for the ealrier 69 model??

PS: What's the difference between a 225 MM disk for a 70-71 and a 225mm disk for 72-86??

Grady Clay · 03-06-2006, 06:05 AM

Bob,

Quote:

What's the difference between a 225 MM disk for a 70-71 and a 225mm disk for 72-86??

It is the internal splines for the input shaft.

Best,
Grady

rw7810 · rw7810's Garage

Well, I got the engine back in this weekend, hooked up and fired up. Clutch is smooth as silk. New 1st gear syncro really makes a difference. No more dropping it in 3rd first. Used the Bosch distributor grese as Randy suggested for the ball pin and throwout fork. Whaoo.